Guidewire with non-tapered tip

Abstract

The present invention relates to a guidewire which comprises an elongated core of a substantially solid cross-section having a distal end portion, the distal end portion having a plurality of notches therein, the notches having a depth of 5-25% of the diameter of the proximal end. The proximal end of the guidewire has a diameter in the range of 0.005-0.040 inches, the notches defining a continuous helix with a constant depth. The guidewire also comprises a helically wound spring, the spring having a plurality of coils defining a lumen. At least part of the distal end portion of the elongated core being received within the lumen. That part of the distal end portion of the elongated core being received within the lumen forming with the helically wound spring an intermediate portion, at least a portion of the coils being disposed within the continuous helix of the elongated core, the helically wound spring being sized and positioned on the elongated core such that a smooth continuous outer diameter is attained over the length of the guidewire. The guidewire also has a means for bonding the coils to the distal end portion so that the guidewire has a continuous stiffness gradient along the length of the guidewire from a stiffest point at the proximal end to a more flexible portion in the distal end portion proximal to the intermediate portion, to a still more flexible portion in the intermediate portion to a most flexible point at the distal end of the helically wound spring. In an alternative embodiment the notches define a continuous helix with a constant depth. This alternative embodiment also has a rounded tip connected to the distal end of the spring and a safety wire connecting the distal end portion and the rounded tip.

What is claimed is: 
     
       1. A guidewire comprising: an elongated core of a substantially solid cross-section having a proximal end and a distal end portion, the distal end portion having a plurality of notches therein, the notches having a depth of 5-25% of the diameter of the proximal end, the proximal end having a diameter in the range of 0.005-0.040 inches, the notches defining a continuous helix with a constant depth;   a helically wound spring, the spring having a proximal end, a distal end, a plurality of coils, and defining a lumen, at least part of the distal end portion of the elongated core being received within the lumen, the part of the distal end portion of the elongated core being received within the lumen forming with the helically wound spring an intermediate portion, at least a portion of the coils being disposed within the continuous helix of the elongated core, the helically wound spring being sized and positioned on the elongated core such that a smooth continuous outer diameter is attained over the length of the guidewire, and   means for bonding the coils to the distal end portion,   so that the guidewire has a continuous stiffness gradient along the length of the guidewire from a stiffest point at the proximal end to a more flexible portion in the distal end portion proximal to the intermediate portion, to a still more flexible portion in the intermediate portion to a most flexible point at the distal end of the helically wound spring.   
     
     
       2. The guidewire according to claim 1, further comprising: a) a rounded tip, connected to the distal end of the spring; and   b) a safety wire, the safety wire having a first end and a second end, the first end being connected to the distal end portion, the second end being connected to the rounded tip.   
     
     
       3. The guidewire according to claim 1 wherein the elongated core is selected from the group consisting of stainless steel and nickel titanium alloys. 
     
     
       4. The guidewire according to claim 1 wherein the distal end portion tapers from a larger diameter adjacent to the proximal end to a smaller diameter distally. 
     
     
       5. The guidewire according to claim 1 wherein the distal end portion is a straight taper from the proximal end of the distal end portion to the distal end. 
     
     
       6. The guidewire according to claim 1 wherein the distal end portion is a smaller diameter than the proximal end. 
     
     
       7. The guidewire according to claim 1 wherein the distal end portion is smaller in diameter than the proximal end and tapers from a larger diameter adjacent to the proximal end to a smaller diameter distally. 
     
     
       8. The guidewire according to claim 1 wherein the distal end of the distal end portion is smaller in diameter than the portion of the coils being disposed within the continuous helix of the elongated core. 
     
     
       9. A guidewire comprising: an elongated core of a substantially solid cross-section having a proximal end and a distal end portion, the distal end portion having a plurality of notches therein, the notches having a depth of 5-25% of the diameter of the proximal end, the proximal end having a diameter in the range of 0.005-0.040 inches, the notches defining a continuous helix with a constant depth;   a helically wound spring, the spring having a proximal end, a distal end, a plurality of coils, and defining a lumen, at least part of the distal end portion of the elongated core being received within the lumen, the part of the distal end portion of the elongated core being received within the lumen forming with the helically wound spring an intermediate portion, at least a portion of the coils being disposed within the continuous helix of the elongated core, the helically wound spring being sized and positioned on the elongated core such that a smooth continuous outer diameter is attained over the length of the guidewire;   means for bonding the coils to the distal end portion;   a rounded tip, connected to the distal end of the spring; and   a safety wire, the safety wire having a first end and a second end, the first end being connected to the distal end portion, the second end being connected to the rounded tip;   so that the guidewire has a continuous stiffness gradient along the length of the guidewire from a stiffest point at the proximal end to a more flexible portion in the distal end portion proximal to the intermediate portion, to a still more flexible portion in the intermediate portion to a most flexible point at the distal end of the helically wound spring.   
     
     
       10. The guidewire according to claim 9 wherein the elongated core is selected from the group consisting of stainless steel and nickel titanium alloys.